I know it depends on the water cycle, but I don’t know more
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Water evaporates – gets heated by the sun and earth (think steam of boiling water)
Goes up in the sky
Collets together when it cools down
Forms a cloud
Could gets heavy with too much water
Then it rains down
Water evaporates into water vapor. It goes up into the atmosphere where it cools and condenses into water droplets that fall down as rain.
Water has 3 states; gas, liquid and ice.
When enough of the gas state particles in the air have combined they reach the liquid state and gravity brings them down.
Water doesn’t have to be at its boil point to evaporate. More so, the water in the oceans and lakes and everywhere exposed to open air slowly evaporates according to how hot it gets. The colder it is, the less evaporation will happen. Even if it gets to ice temps (32F) the air can still hold moisture in it. Just not enough to create normal rain. Even at lower temperatures, there can be a little bit of moisture but as it gets colder, water starts to dwindle from the air. All liquids evaporate like water, just at different temperatures.
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The atmosphere has water molecules in it. We often refer to the amount of water in the air as humidity. We usually use *relative* humidity to talk about how much water is in the air, and that’s a percentage. A percentage of what? The amount of water that would be in the air at that temperature if it were surrounded by water.
At the water surface fast water molecules will sometimes break free from the liquid and go into the air. Similarly, some of the water molecules in the air will hit the liquid and rejoin. When there are very few water molecules in the air, more molecules escape the liquid than rejoin, causing net evaporation. When there’s a lot of water molecules in the air more water molecules rejoin than escape, causing net condensation. When the rates are balanced we call that equilibrium and 100% humidity.
The rates of escaping and rejoining change with temperature. This means that 100% humidity is actually a different amount of water at different temperatures. So if you take 100% humidity air at 70°F and cool it to 50°F your humidity would be 180%! That water really wants rejoin to become liquid.
If there’s dust or other nucleation sites in the air with all those water molecules then they might “rejoin” on the surface of the dust and grow into tiny water droplets like mist. This is what you see when you see a cloud, hundreds of thousands of tiny water droplets reflecting and refracting light till it looks white, just like the fibers in paper.
Finally, if there’s enough tiny droplets and they are still growing then they start running into each other and combining into bigger droplets. There have to be a lot of droplets for this to happen which is why rain clouds look darker, there’s more droplets so less light makes it through. When the droplets get bigger and heavier they start to fall faster and faster, finally becoming rain.
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